package cn.sdhuijin.interceptor;

import java.io.PrintWriter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import cn.sdhuijin.model.User;

/**
 * @author sunp@sdhuijin.cn
 * @version 创建时间：2015年1月14日 下午1:54:55 拦截器
 */
public class CommonInterceptor implements HandlerInterceptor {

	/**
	 * 在DispatcherServlet完全处理完请求后被调用
	 * 
	 * 当有拦截器抛出异常时,会从当前拦截器往回执行所有的拦截器的afterCompletion()
	 */
	@Override
	public void afterCompletion(HttpServletRequest arg0,
			HttpServletResponse arg1, Object arg2, Exception arg3)
			throws Exception {

	}

	// 在业务处理器处理请求执行完成后,生成视图之前执行的动作
	@Override
	public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1,
			Object arg2, ModelAndView arg3) throws Exception {

	}

	/**
	 * 在业务处理器处理请求之前被调用 如果返回false 从当前的拦截器往回执行所有拦截器的afterCompletion(),再退出拦截器链
	 * 
	 * 如果返回true 执行下一个拦截器,直到所有的拦截器都执行完毕 再执行被拦截的Controller 然后进入拦截器链,
	 * 从最后一个拦截器往回执行所有的postHandle() 接着再从最后一个拦截器往回执行所有的afterCompletion()
	 */
	@Override
	public boolean preHandle(HttpServletRequest request,
			HttpServletResponse response, Object handler) throws Exception {
		Boolean flag = false;
		HttpSession session = request.getSession();
		User currentUser = (User) session.getAttribute("currentUser");
		String head = request.getHeader("X-Requested-With");
		if (head != null && head.equalsIgnoreCase("XMLHttpRequest")) {
			if (currentUser == null) {
				response.setHeader("sessionstatus", "timeout");
			} else {
				flag = true;
			}
		} else {
			if (currentUser == null) {
				PrintWriter out = response.getWriter();  
                StringBuilder builder = new StringBuilder();  
                builder.append("<script type=\"text/javascript\" charset=\"UTF-8\">");  
                builder.append("alert(\"登入超时,系统将自动跳转到登陆页面,请重新登入!\");");  
                builder.append("window.top.location.href=\"");
                builder.append(request.getContextPath() + "\";</script>");  
                out.print(builder.toString());  
                out.close();  
			} else {
				flag = true;
			}
			// response.sendRedirect(request.getContextPath()); //后期拦截get请求
		}
		return flag;
	}
}
